Apparatus for making sheet glass



APPARATUS FOR mmm@ SHEET GLASS Filed May 7, 1925 2 Sheets-Shee'; l

I l Ii l Ii l1 l l; l n i l* F. GIELEVHWAWF APPARATUS FOR MAKING SHEET GLASS Filed May 7, 1923 2 Sheets-fhefaiz 2 Patented' 0a.` 19, 1926.

FREDERICK GELSTIIARP, 0F TARENTUM, PENNSYLVANIA, ASSIGNOR T0 PITTSBURGH PLATE GLASS COMPANY, A CORPORATION OF PENNSYLVANIA. I

APPARATUS FOR MAKING SHEET GLASS.

Application ld May 7, 1923. Serial No.\637,128.

The invention'relates to the manufacture of sheet or plate glass, and has :for its objects the provision of an improved apparatus for producing glass in a continuous sheet or ribbon from a tank, preferably.

from a melting tank of the regenerative type. Certain embodiments of the invention are illustrated in the accompanying drawings wherein:

Figure 1 is a vertical section through the apparatus. Fig. 2 is a transverse section on the line II-II of Fig. 1. Fig. 3 is a diagrammatic end view ofthe gearing for driving the rolls. And Fig. 4`is a diagrammatic sectional view illustrating a modiiication of the structure of Fig. 1 wherein the second pair of rolls are placed at a level below that of the first'pair.

Referring to the drawings, 1 is the discharge end or forehearthl of a continuous melting tank containing a bath of molten glass 2. The side wall 3 is made in theform of a separate block carried by the metal framework 4 so that it may be readily removed for replacement or repair and is provided with an outlet slot 5 adapted to discharge to the reducing rolls 6 and 7, such roll-s being driven'as hereinafter described and being hollow` and provided with connections 8 and 9 whereby liquid may be supplied to maintain the rolls atany desired temperature. The rolls are carried upon the truck frame 10, and the truck itself is mounted upon the rails 11 which arrangement permits of the movement of the truck laterally when it is desired to repair or replace Athe rolls and to give access to the slot member 3.

Also mounted upon the truck framework is a second pair of driven water cooled rolls 12 and 13, such rolls being supplied with a cooling medium through connect-ions, not

shown, but corresponding to the connections 8 and 9. The truck also carries shade members 14 and 15 supported in a suitable framework of channels and T bars 16 and 17 and a water cooled supporting roll i8 intermediate the two sets of reducing rolls. ln some cases it is necessary to employ burners 19 intermediate the two sets of rolls, such burners ordinarily being located adjacent the edges of the sheet which are apt to cool most rapidly, although in some cases it may be desirable to apply heat tothe entire width of the sheet.

provided with suitable slots or perforations for directing the air against the lips. The spaces at the ends of the rolls 6 and 7 are preferably closed by triangular metal members 24 which are preferably heated as fully described in my Patent No. 1,560,078 of Nov. 3, 1925. l

The shafts of the rollers are provided with tumblersh'afts 25, 26, 27 and 28 (Figs. 2 and 3). The shatts 25 and 26 are provided with the intermeshino' spur gears 29 and 30, the lshaft 26 also being provided with a gear 30a which is driven from the pinion 31 011 the shaft 32. The shaft 32 is driven from the motor 33 through the intermediary of -the worm reducing mechanism in the casing 34.

The pinion 31 also drivesa spur gear 35 carried by the tumbler shaft 28- (Fig. 3). This shaft 28 carries a spur gear 36 meshing with a similar gear 37 on the tumbler shaft 27. Since the gear 35 is ofless diameter than the gear 30, this arrangement provides for driving the rolls '12 and 13 faster than. the rolls 6 and 7, this being necessary be cause the portion of the sheet at 38a must `,travel fast-er than the thicker portion at Intermediate the two sets of rolls the supporting roll 18 which is necessary to pre-l vent the sheet from sagging at this point. @ne or more rolls may be employed depending upon the distance apart of the two sets of reducing rolls, and these rolls may either be idlers or maybe driven. but are preferum ably driven as illustrated, this being accom plished by means of a sprocket 39 which is driven by the sprocket chain 40 passinv around a sprocket wheel 41 on the shaft o? the roll 7..

ln advance of. the rolls 12 and 13 is a leer 42, which may be of any desired type, but vis preferably provided with rolls 43 having sprockets 44 on their ends driven from the chain 45. The damper 46 is preferably employed at the inlet end of the leer, such damper being supported from cables 46 passing over suitable pulleys and counterweighted.

of angle irons, prefernichrome or other suit-y While the second pair of reducing rolls 12 *and 13 are preferably located on the samey first reducing rolls, such rolls departing from the invention which contemplates broadly the use of sizing means to give the` sheet its final dimension after passing the first set of rolls which act to .control the flow of glass from the tank under the head pressure .in such tank. The tendency toward 'devitrification is. reduced where two or more sets of rolls are employed, instead -of accomplishing all ofthe reduction by a single pair of rolls at theoutlet of the slot 5, and the placing of the secondary rolls at the same level as the first rolls has the ad- `vantage of avoiding the necessity of A the trolls.

straightening the sheet again, .such as is called for when the sheet is carried to a lower level after' passing the rolls 6 and 7 and then turned tothe horizontal again on entering the leer. This same advantage is present when .all ofthe reduction of the thickness of the sheet is acomplished by the first pair of rolls `6 and 7, in which case the rear end ofthe leer 42 can be brought back closer to the rolls 'and 7. The tendency toward devitrification, referred Ito above, which' exists when a. single pair of rolls is used and all the reduction occurs in the one pass, is believed to be, due to the existence of amore or less stagnant body of glass of relatively small volume immediately behind The glass above and below this volume of glass is positively fed between the rolls because of its contact with the forwardly moving roll surfaces leaving the glass between the two layers thus fed forwardly in a condition of rest and at a temperature (due to the proximity to the rolls) such that devitrification is liable to occur sooner or later, thus introducing into the sheet from time to time small volumes of glass of light color which impair the quality of the glass. With a wider pass between the rolls, there is greater opportunity for the body of glass trapped between the rolls behind the pass to flow forward between the layers of glass pulled forward by the roll surfaces, so that the glass at this point is fed out and replaced by fresh glass in a reducedinterval, thus reducing its liability to devitrify.

What I claim is:

l. In apparatus for making sheet glass continuously in a sheet or ribbon. the combination with a tank or receptacle for molten lass providedy with an outlet through its side wall so located as to pernt the diS- of Fig. 4. Only a single pair charge therethrough under the head pressure of the tank, of sheet forming rolls at suclroutlet with their pass under said head pressure arranged to control the rate of fiow of the glass from said outlet and spaced apart a distance greater than the thickness of the finished sheet, and a second pair of rolls in advance of the first pair spaced aparta less distance than such first pair andserving to reduce the thickness of the'vsheet or ribbon.

2. In apparatus for making sheet glass continuously in a sheet or ribbon, the combination with a tank or receptacle for molten glass provided with an outlet through its side wall so located as to permit the discharge therethrough underthe head pressure ofthe tank, of sheet forming rolls at such outlet with their pass under said head pressure arranged to controlfthe rate of flow of the glass from said outlet and spaced .apart a distance greaterithan the thickness of the finished sheet, a second pair off rolls in advance of the first pair spaced apart a less distance than such first pair, and a leer in `advance of said second pair of rolls.

3. In apparatus for making sheet glass continuously in a sheet or ribbon, the combination with a tank or receptacle for molten Vglass provided with an outlet through its side wallso located as to permit the 'discharge therethrough under the head pres-- permit the discharge therethrough under the hea d pressure of the tank, of sheet forming rolls at such outlet 'with 'their pass under said head pressure arranged to control the rate offlow ofthe glass from said outlet and. spacedhpart a` distance greater than the thickness of the finished sheet, sizing rolls in advance of said rolls for giving the sheet its finall thickness, and a leer in advance of said sizing rolls. y

5. In apparatus for making sheet glass continuouslyY in a sheet or ribbon, the combination with a tank or receptacle for molten glass provided with an outlet through its side wall so located as to permit the discharge therethrough under the head pressure of the tank, of sheet forming rolls at such outlet with their pass under said head pressure arranged to control the rate of flow of the glass from said outlet and spaced apart a distance greater than the thickness ing at substantially the same level so that of the finished sheet, sizing rolls in advance the sheet is maintained throughout in sub- 10 of said rolls for thinning the sheet or ribstantially a single plane. bon and giving it a dehnite. and uniform In testimony whereof, I have hereunto 5 thickness, and a leer in advance of the sizsubscribed my name this 2nd day of May,

ing rolls having a bed for forwarding the 1923. sheet or ribbon therethrough, the passes be tweenthe rolls and the bed of the leer 1y- FREDERICK GELSTHARP. 

